The present invention relates to improvements in and/or relating to mineral breakers and in particular (although not solely) the contouring of the rotor bed of such machines.
Our mineral breaker was first disclosed in Australian Patent Specification No. 463819. Such a mineral breaker was revolutionary at the time since it embodied a system whereby a plurality of the mineral beds are defined within a rotating element (rotor) thus ensuring the majority of the wear (save for a hardened wear tip) is of mineral against mineral.
Enhancements of the original machine are disclosed in our New Zealand Patent Specification No. 198307 (AU 557168), 201190 (EPO 101277 and AU 562251), 201418, 213510, 217752, 217753, 222648 and 250027 (WO 95/11086).
Our New Zealand Patent Specification 201190 discloses an improvement whereby, as an enhancement, a hardened wear tip blade is mounted within a recess at the edge of a carrier which is to be positioned at a position where, in the manner of a weir, the smaller pieces of mineral overflow to exit the device.
U.S. Pat. No. 2,992,783 (Wirth et al) also show a mineral breaker of a kind having a substantially vertical axis feed into a rotor.
U.S. Pat. Specification No. 4,940,188 of J Rodriguez and D Rodriguez discloses yet a further refinement of the system. This U.S. Patent discloses the use of a weir member which acts substantially as a straight edged wear tip but which better manages the weir erosion.
New Zealand Patent Specification 248953 (WO 95/10358) Tidco International Limited discloses yet a further refinement of the weir tip aspects.
In our WO 95/111086 there is disclosed and claimed a variety of tip defining assemblies for inclusion in a rotor of such a mineral breaker, the weir-like edge being configured, assembled or otherwise arranged to provide a region of flow enhancement such that a greater depth of mineral pieces passes over that edge region favoured to be eroded and to retain a bed of material having a transverse surface conforming to the weir-like edge. Symmetric contours for such a weir-like edge are defined with the preferred forms being to a V, U or other scalloped configuration.
The full content of all of the aforementioned specifications is hereby here included by way of reference.
Attention is also drawn to our as yet unpublished New Zealand Patent Specification Nos. 299518 and 299299.
The present invention is directed to mineral breakers, sub-assemblies and operating procedures and methods when using such mineral breakers which provides at least an alternative to the rotor retained beds derivable from such prior art devices and preferably in a form that enhances a transition for pieces to be broken from (i) a flow stream substantially parallel to the rotor axis to (ii) the radial flow with respect to the rotor over the weir-like edge into a crushing surface defined by a retained mineral lining or bed impingement surface of a surrounding chamber or into a xe2x80x9ccrushingxe2x80x9d zone (which may or may not involve passage of the mineral pieces to that surface through a cascade of a secondary or rotor bypassing feed of mineral pieces or through rebound or deflected pieces).
As used hereinafter reference to xe2x80x9ccrushingxe2x80x9d embodies the breakage of materials (preferably minerals) by mineral to mineral impact and/or mutual abrasion.
Moreover whilst a rotor will be defined preferably with reference to three retained beds of mineral pieces in the rotor any number of such retained beds is within the scope of the present invention.
Likewise xe2x80x9cmineralxe2x80x9d can mean any material capable of breakage into pieces by mutual collisions.
Likewise xe2x80x9cplatexe2x80x9d is to be construed broadly to include any unitary or fabricated form whether spaced apart or not.
Accordingly in a first aspect the present invention consists in
A rotary mineral breaker of a kind, having a rotor to rotate about a substantially vertical rotary axis, the rotor having an inlet for mineral pieces at and/or substantially parallel to the rotary axis thereof from above and at least one peripheral exit port for such materials to exit in the same and/or a modified form radially of the rotor into a surrounding mineral material interaction zone, the rotor being characterised in that at the or each peripheral port, but carried by said rotor, there is means providing an exit port geometry which at least includes a mineral piece bed accumulation weir to encourage, by appropriate profiling of the bed, those mineral pieces accelerating in use on the bed of retained mineral pieces to exit over the weir(s) away from the upper regions of the retained bed.
Preferably the or each weir favours material exiting at and/or below the mid point of the axial depth of the retained bed;
Preferably the or each weir favours material exiting at lower regions of each weir;
Preferably the bed associated with the or each peripheral port is further shaped by the provision of rotor carried means to provide a bed trailing geometry such that the retaining bed of the rotor is shaped between the bed trailing geometry and the exit port geometry to provide, by the profiling of the bed, a favoured curved locus for mineral piece movement upon entry in use into the rotor downwardly over the bed to the peripheral port;
Preferably each weir is asymmetric when considered in its vertical extent;
Preferably each weir includes at lease one sacrificial member carried by a member or assembly in turn carried by the rotor;
Preferably there are a plurality of peripheral ports.
Accordingly in another aspect the present invention consists in, in a rotary mineral breaker of the aforementioned kind, the use of a rotor to rotate about a substantially vertical rotary axis and having an inlet for mineral pieces substantially parallel to the rotary axis thereof from above (and preferably at or adjacent the rotary axis thereof) and having at least one peripheral exit port for such materials in the same or a modified form, the rotor being characterised in that at each peripheral port but carried by said rotor a member, structure or assembly defines a mineral piece bed accumulation weir for the rotor and said geometry thereof (exit port geometry) is such as to favour the exiting of mineral pieces in use over a retained bed of retained mineral pieces over an edge or edges of the geometry away from (when viewed in use) the upper regions of the retained bed.
Preferably said geometry is asymmetric.
Preferably said geometry is in the form of a plate or number of plates (preferably with hardened weir-like edges).
Preferably said edge favours material exiting at and/or below about the midpoint of the axial depth of the rotor port.
Preferably said rotor includes a member, structure or assembly to define a bed trailing geometry and the retained bed of the rotor is in each instance retained between the two geometries, ie; the trailing geometry and the exit port geometry.
Preferably the trailing geometry is such as to reduce the proximate retained bed at the upper regions of the axial depth of the rotor in favour of greater bed retention at the lower regions thereof
Conversely preferably the exit port geometry does substantially the opposite.
Preferably the trailing geometry includes no hardened surfaces but preferably is configured so as to enhance bed accumulation and the tuning thereof to define the preferred locus of movement over the retained bed for mineral pieces that come into contact with the retained bed.
Preferably a favoured locus of mineral piece movement upon entry in use into the rotor downwardly is about a curve (preferably to exit adjacent lower regions of the retained bed).
In yet a further aspect the present invention consists in a rotary mineral breaker of a kind as previously set forth in any of its forms wherein a weir-like tip or tip assembly defines an overflow edge (at least part of which is to be sacrificed but which preferably is of a hardened material) wherein the weir-like surface is asymmetric and is attachable into the rotor so that the weir will have a reduced affect and thus favour overflow (preferably at lower regions of the rotor as against upper regions thereof).
Preferably said tip assembly is of any of the kinds previously defined but with pre-defined wear hardened elements embodied therein, thereon, etc., eg; tungsten carbide, etc.
Preferably the assembly is of any of the kinds previously set forth when modified to take into account the asymmetric requirement just mentioned or to take into account the preferred requirements thereof in respect of tuning a retained bed of a rotor in conjunction with a trailing geometry as previously set forth.
In still a further aspect the present invention consists in a rotary mineral crusher of any of the aforementioned kinds (whether to be operated with a single flow) through the rotor or as a dual flow (ie; through the rotor and separately cascaded down about the rotor) where embodied in the machine there is a rotor of the kind previously defined preferably with the weir-lie geometry defined at the outlet port(s) thereof or having a trailing geometry defined therein as previously defined, or both.
In preferred forms of the present invention preferably the rotor is provided with sufficient axial dimension to enable a smooth curving flow of mineral pieces to pass through the device.
Preferably said rotor embodies a circular or equivalent plate (preferably not having a stepped down periphery thereof but which may be stepped once or several times down to enhance such an effective depth to facilitate a curved flow path for mineral pieces) and which preferably has a central cone or the like, the apparatus being operable such that in use mineral pieces flow down into the spinning rotor and follow a favoured locus of movement over the (or each) retained bed over the weir-like exit port geometry of the (or each) bed.
In still a further aspect the invention consists in a rotary mineral breaker of a kind having a multiple bed carrying rotor that has an infeed at least substantially centrally from above substantially parallel to the rotation axis of the rotor where means is provided to effect bed contouring to a sacrificial weir-like effect structure, assembly or the like is achieved to define a preferred mineral piece curving locus of migration determined by contouring of the bed surface transverse to said locus, said curving locus passing over a predetermined wear resistant part of said sacrificial structure.
In still a further aspect the present invention consists in a weir-like geometry (whether defined as an assembly or an assemblage of components or whether unitarily defined or otherwise fabricated) where the effective sacrificial weir-like surfaces thereof favour movement over the sacrificial surface at lower regions of the rotor with respect to its vertical axis.
Preferably the assembly can take any of the forms previously described by reference to prior art wear tip assemblies.
In still a further aspect the present invention consists in a method of operating a rotary mineral breaker which comprises feeding mineral pieces to be crushed into the rotor of such a mineral breaker and by appropriate assembly of the bed retaining geometries at the exit port and at the trailing region of the retained bed defining a valley like surface of retained mineral pieces that curves downwardly and outwardly to the favoured exit region or regions of the weir-like edge of the exit port.
Preferably said method is performed using any of the apparatus previously defined.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.